This invention relates to a combustion heating system and more particularly one employing a unit having a porous ceramic reactor contained within a casing.
Gas fired porous ceramic reactors for generating an intense heat have been known and used for an appreciable period of time. A radiant gas burner incorporating such is described in U.S. Pat. No. 3,191,659 issued June 29, 1965, and another is described in connection with a space heater in U.S. Pat. No. 3,179,156 issued Apr. 20, 1965. Widespread use of these ceramic reactors for the heating of an entire home or building has been limited for a number of reasons. Among the reasons are the problems of disposing of the waste products, particularly carbon monoxide and carbon dioxide, that result from the burning of the gaseous fuel. It is important that these products not be emitted in any large quantities within the room or dwelling being heated. Another requirement that has been difficult to meet is the need for a safe, gas tight system from inlet to outlet to avoid having the gas fuel as well as the products of combustion seep into the spaces or room that is being heated. Another requirement is that the gas fired system be explosion proof to an extremely high degree of reliability.
Accordingly, among the purposes of this invention is to achieve such in a fashion that provides a high degree of efficiency in the transfer of heat from the ceramic radiant burner to the area to be heated.
It is a related purpose of this invention to provide a system in which the combustion of the gas will be as nearly complete as possible so as to be fuel efficient and to minimize pollutants.
Various applications for the use of a contained reactor for heating a boiler, or the like, will call for a range of heating capacity. In smaller systems one or two of the reactor elements will be required. Accordingly, it is a purpose of this invention to provide a heating unit design which meets the above objects and is sufficiently modular in form so that any required number can be selected for a particular installation.
When a plurality of reactor elements are involved, the ignition power required may be substantial. However, if the reactor elements can be ignited in sequence, the power capacity of the ignition generator can be minimized. Accordingly, it is a further purpose of this invention to provide a technique for simply and reliably sequencing the ignition of the reactor elements in a multi-element system and to do so in a fasion that assures that combustion has been achieved in one unit before the spark is removed from that unit.
It is important that the system be shut down if or when there is a failure of combustion. Specifically, it is important that the system stop pumping fuel and that voltages be removed if either ignition is not achieved when the system is turned on or if combustion is lost after the system has been running. It is important that the safety shutdown mechanism be simple, reliable and inexpensive. Yet it is also essential that the shutdown mechanism not respond to the interim condition that exists when the system is initially turned on. Thus, it is a further purpose of this invention to provide a safety shutdown system that accepts the interim conditions which occur during the initiation of ignition yet adequately responds to comparable conditions that indicate a failure of ignition or loss of burning.